Improvement in locks for pianos



Titti-1rd,* gamine HERRMANN AHREND, 0F NEWARK, NEW' JERSEY.

Letters Patent No. 107,585, daterlvSeptcmber 20, 1870.

IMPROVEMENT IN LOCKS IE'R PIAN'OS, Gac.

The Schedule referred to in theseLettgrB Patent and making. part of the same To all whom t may concer-n Be it known that I, HERRMANN AHREND, of Newa1'k,iu the county of Essex'and State of New Jersey, have invented a new and useful Improvement tumbler, provided with a T-head, which engages with' notches iuthe inner ends of two oscillating h ooks, in such a manner that, when the sliding tumbler is forced np, both hooks are simultaneously thrown in; and when the tumbler is forced down, both hooks 'are simultaneously thrown out, in their locking position,

and retained there against any force which may be brought to bear upon their outer ends', while the whole locking mechanism is exceedingly simple, being' composed of not more than three pieces, viz., the two vhooks and the sliding tumbler.

In the drawing- The letter Adesiguates the plate which supports the various parts composing the working mechanism of my lock, and which is connected to the facefplate B n .In the plate Aare secured two studs, c c, which Aform the -fulcrums for the hooks b b.

The heads of these hooks are curved, and they move in slots in the face-plate B. Their tail ends are provided with notches, c c, to-engage with the ends d d of a T- headed slide, e.

This slide forms 'the tumbler of the lock. It is provided witha slot, j; one edge of whichis camshaped, and forced up against a stud, g, by the action.

of Aa spring, h. Before the slide can be moved up lor down it has to be forced back against the action of the 'spring h,.so as to-throw -the stud g clear of the cam-shapededge ofthe slot f, and, by moving the slide down,l from the positioushowu in lig'. l to that shownin g. A2, thehooks b b are simultaneously thrown out, and, since the tumbler is locked by the'action of the cam-shaped slot fand stud g, no force brought to bear on the outer'ends of either or both hooks is ca-v Y pable to throw Athe same back.

By reversing the motion of the slide e the hooks are returned to the position shown in iig. 1. The motion of the slide eis effected either by the bit of a. key, as indicated in fig. 2 of the'drawing, or

a nut may be used, which is operated by. a.- key with a squarereud.

^ By these means a ldck is obtained which is exceed- .ingly .simple in its-construction, its locking mechanism beiug' composedfof notmorel than thi-ee parts'and one spring, and,at the same time, the hooks, when in their locking position, cannot' be vforced back by pressure applied to their outer ends, and when the h'ooks are thrown back they completely -ll their openings in the face-plate of .the lock.

What I claim as new, and desire to secure by Letg 'lhe sliding tumbler e, provided with a T-head, which engages with the notched ends of two hooks, b b, slbstantially in the manner herein shown anddescri ed.

HERRMANN AHREND.

Witnesses:

W. HAUFF, C. WAHLERS. 

